There are vertical wall to prevent of circulation or pollution during building of ocean structures like a dam and bridge in the harbors area and the sea. Inflow fluid and base of structure are important thing as one of the structural design factors for this interception wall like a vertical wall and watertight wall. In this study, it is revealed that at least 2,000 instantaneous velocity field data are required for ensemble average to get reliable turbulence statistics. The flow behind of vertical wall was investigated using the PIV system from this study. From the results, the large vortex flow developed in recirculation zone for one row wall and two vortex flows developed over two rows. Scale of the vortices in recirculation zone was decreased to 45% over three rows.

In this study, we have modeled a wide angle diffuser with rectangular prism and tried to investigate the influence of a turbulent wake flow by PIV and a numerical simulation using computational fluid dynamics based on steady-state Navier-Stokes equation and standard k-ε model. A commercial CFD program, FLUENT, is used on the analysis. The turbulent wake is generated by a rectangular prism, which is installed at the diffuser. The results show that it is possible to flow control by installing a rectangular prism within the diffuser and velocity recovery is the highest in aspect ratio 1:1.

In an online environment, hedonic value such as flow is manifested when consumers continuously engage in playing online games even if it incurs extra cost: financial, physical, and psychological. Consumers also have a loyalty to their games, and they enjoy playing them. They often purchase repeatedly games they are involved in. The framework of existing online game models does not fully explain flow and telepresence to loyalty and the purchase intention of game decision-making behavior. For this reason, we examined the relationships among telepresence to flow, flow to loyalty, and loyalty to purchase intentions. Study 1, which is a behavioral analysis by SEM (Structural Equation Modeling), examines how “flow and telepresence” influence loyalty and purchase intention in an online game behavior. The introduction of hedonic perspectives as flow and telepresence produced an important extension of the online game model. The conceivable factors which may explain this type of consumer behavior are the hedonic or experiential aspect of consumer behavior. We have three hypotheses. All hypotheses are supported at 0.1% significance level. Study 1 focused on the relationships of the constructs of the online game. We also measured the state of flow while game users are playing online games by EEG (Electroencephalogram). In a neural analysis, we found that the state of flow and neural correlates exist. By this, the flow variable reflects the real mental “state of flow.” Study2, which is a neural analysis, examines flow construct in the FPS game Call of Duty: Modern Warfare 2 by using Electroencephalogram (EEG). How much flow do the subjects experience while playing this online game? The purpose of this research is to select the epochs of EEG data when the subjects reported flow, correlate those with flow variables, and compare the EEG activity. The final goal is to select the flow variables which showed the highest correlation to AEP (Auditory Evoked Potential) Suppression value. We analyzed 8 AEPs to correlate flow. We found out that Alpha_RF is casually decided with the mean of flow which has six variables. Mean of Flow correlated to Alpha_RF -.419 significantly (5%). As subjects feel Flow, Alpha_RF is suppressed. This study focuses on the subjective flow experience and AEP suppression. We found out that the state of flow and neural correlates exist. By our analysis, the flow variable reflects the real mental “state of flow.” Therefore, when game companies develop their games, they should take into account how much flow people feel while they are playing the games. In addition, the state of flow should be used not only in developing and designing games but also in sports, entertainment, etc.

Adventure tourism accounted for 60% of international tourism activities by the year 2007 and is still growing. Nonetheless, relatively little is known about the ecological issues associated with adventure tourism. To address this issue, this study examines 502 Chinese tourists’ intentions to revisit adventure tourism activities by incorporating nature-relatedness (i.e., NR-self, NR-perspective, and NR-experience) into a modified flow model. After analyzing these data by structural equation modeling, our findings show that positive emotions and flow experiences influence one’s intentions to revisit adventure tourism activities and that then intensity of the flow experiences is influenced by skill, perceived challenge, and playfulness. Moreover, our study finds that tourists who enjoy being outdoors (NR-experience) and who find conservation unnecessary (NR-perspective) are likely to have a more positive attitude about adventure tourism. Conversely, individuals who are concerned about the environment will not have such emotions. The implications of these findings for such promotions are discussed.

The basis of the cobalt demand analysis by use was established via the investigation and analysis of the cobalt materials flow, and the overall cobalt metal material and parts industry structure in Korea was examined to determine the cobalt material flow. The markets of the cobalt material for machinery were studied, including their interrelations, via market and study trends, and relevant plans were examined. The results of the study indicated that the advanced core technology for advanced industry and technology-intensive industry development is required to structurally innovate the parts materials and basic materials industries and to upgrade the catch-up industry structure to the new frontier structure.

This research is to investigate the performance analysis of fuel cell for flow channel with four different types of the channel (Serpentine I, II, Inter-digitated, Parallel) in the fuel cell stack. Velocity, pressure. and temperature distributions of fluid over the flow domain of the flow channel are numerically calculated for the optimum design of flow channel with unifrom inlet velocity. According to the calculations of low pressure drop between inlet and outlet in the flow channel, Serpentine I type is of highest performance of the flow channel shapes in the present fuel cell model.

This study is done as a comparison analysis on existing studies on analysis and interpretations of solenoids. When there is no power in a solenoid valve, a flow passage is formed from a pressurized ports, Pc, to Ps, which are connected to a crankcase of a pressurizer. An inlet to Pc port is varied in three different sizes: 3.8 ㎜(Type-1), 4.0 ㎜(Type-2) and 4.2 ㎜(Type-3). It is determined that there will be changes in coolant flow into the solenoid valve and the flow properties from Pc port to Ps port are compared and analyzed. As the results, the flow demonstrates the maximum speed of 500 ㎧, 46 ㎧ and 433 ㎧ with 0.2 ㎫ for the inflow pressure and the maximum speed of 1400 ㎧, 129 ㎧ and 1200 ㎧ with 1.5 ㎫ for the inflow pressure.

Water discolouration and increased turbidity in the local water service distribution network occurred from hydraulic incidents such as drastic changes of flow and pressure at large consumer. Hydraulic incidents impose extra shear stresses on sediment layers in the network, leading to particle resuspension. Therefore, real time measuring instruments were installed for monitoring the variation of water flow, pressure, turbidity and particulates on a hydrant in front of the inlet point of large apartment complex. In this study, it is attempted to establish a more stable water supply plan and to reduce complaints from customers about water quality in a district metering area. To reduce red or black water, the water flow monitoring and control systems are desperately needed in the point of the larger consumers.

바이오가스로부터 폴리설폰 분리막을 이용한 메탄 농축 특성을 수치해석 방법으로 분석하였다. 향류 흐름 분리막공정의 지배 방정식을 유도하고 무차원화 한 후 Compaq Visual Fortran 6.6 소프트웨어을 이용하여 공정모사하였다. 공급 기체의 메탄 몰분율이 0.5인 경우 주어진 전형적 운전조건 상태에서 분리막 길이에 따른 잔류 측의 메탄 몰분율은 시점에서 종점으로 이동하면서 0.5에서 0.8로 증가하였으며 공급유량 대비 잔류유량 비율은 1.0에서 0.57으로 감소하였다. 공급 메탄 몰분율을 0.9로 변화시킨 경우 잔류 측의 최종 메탄 몰분율은 0.93으로, 공급대비 잔류유량은 0.91로 증가하였다. 공급 측 압력이 증가하여 투과 측 압력 대 공급 측 압력 비 값이 0.33에서 0.17로 변경될 경우 단 수율이 0.1과 같이 낮은 영역에서는 잔류 측 메탄 농도 변화가 거의 없는 반면, 단 수율이 0.3과 같이 높은 영역에서는 증가함을 확인할 수 있었다. 분리막 면적이1.14 m2에서 2.57 m2로 증가되면 단 수율의 변화에도 불구하고 잔류 측 메탄 농도가 비교적 높게 유지됨을 알 수 있었다.

본 논문에서는 아이소-지오메트릭 해석법을 이용하여 고주파수를 가지는 파워흐름 문제에 대하여 연속체 기반 형상 최적설계를 수행하였다. 아이소-지오메트릭 기법을 형상 최적설계에 적용하면, CAD 기하 모델링에서 쓰이던 NURBS 기저 함수가 직접 쓸 수 있기에 정확한 기하학 정보가 수치계산에서 고려되고, 이에 따라 형상 최적설계 관점에서 볼 때, 전통적인 유한요소법에 비해 향상되고 부드러운 설계 섭동량을 가지는 설계 매개화가 가능하게 된다. 즉, 정확한 기하 모델이 응답 해석과 설계민감도 해석에 쓰이게 되고, 이에 따라 설계영역 전체에서 법선 벡터와 곡률이 연속적으로 되게 된다. 결과적으로 정밀한 민감도 해석이 가능하게 된다. 몇 가지 수치예제를 통하여 개발된 아이소-지오메트릭 설계민감도가 유한차분 설계민감도와 비교하여 정확성을 확인할 수 있었으며, 형상 최적설계 문제를 통해서 본 방법론을 적용하여 검증하였다.

본 연구는 기존의 게임에 대한 전반적인 부정적 인식에서 벗어나 긍정적인 측면에서 스마트폰 게임을 살펴볼 필요성이 있다고 판단하여 심리적인 측면에서 스마트폰 게임 이용동기와 게임특성이 게임몰입에 미치는 영향을 살펴보았다. 주요 결과를 제시하면, 스마트폰 게임 이용동기는 현실도피, 기분전환, 즐거움, 몰입, 성취 등으로 나타났고, 이 중 현실도피를 제외한 기분전환, 즐거움, 몰입, 성취가 스마트폰 게임몰입에 유의미한 정적 영향을 주는 것으로 나타났다. 따라서 스마트폰 게임 이용자들이 기분전환, 즐거움, 몰입, 성취동기를 추구할수록 게임몰입도 높아지는 것으로 평가할 수 있다. 둘째, 스마트폰 게임특성 중 게임구성, 조작용이성을 제외하고 게임의 생동감은 게임몰입에 유의미한 정적 영향을 미치는 것으로 나타났다. 그러므로 스마트폰 이용자들이 게임을 통해 생동감을 높게 지각할수록 게임몰입이 높아지는 것으로 평가된다. 이상과 같은 결과를 통해 몰입 자체가 건전한 심리작용이고, 스트레스를 해소하거나 여가시간을 즐겁게 보내는데 일정 부분 기여함을 전제로 한다면, 스마트폰 게임 이용이 스트레스를 해소하고 여가시간을 보다 즐겁고 재미있게 보내는데 있어 긍정적으로 작용할 수 있을 것이다. 나아가 일정부분 여가문화 차원으로 활용할 수 있음을 시사한다.

This paper presents the theoretical analysis for the flow driven by surface tension and gravity force in an inclined circular tube. The present study introduces detailed mathematical procedures for Casson viscosity model. The equations of velocity distribution and flow rate are developed to describe the displacement of a non-Newtonian fluid that continuously flew into a circular tube by surface tension. The equation of modified volumetric flow shows the complicated form of (10) due to yield stress term, and the equation of velocity distribution which includes the yield stress and inclination angle of circular tube is composed of terms of r and rc as form of (14).

본 연구에서는 수중 삼각형상구조물의 경사도와 레이놀즈 수 변화에 따른 구조물 주위의 유동특성을 분석하였다. 모델링한 삼각형상구조물 주위의 유동장은 회류수조에서 가시화실험과 입자영상유속계(PIV)를 이용하여 계측하였다. 실험결과 경사각이 45°인 삼각형상구조물이 레이놀즈 수 Re=2.9×10³에서 구조물 높이의 2.7배까지 상승하는 속도성분이 나타났다. 레이놀즈 수가 일정할 때 경사각이 클수록 구조물 후방에 하강하는 속도성분이 크게 나타났고, y/hs=1.75이상의 영역에서는 경사각과 레이놀즈 수가 구조물 후방의 유동형태에 변화를 주지 않았다.

PURPOSES : To solve problems in current compaction control DCPT(Dynamic Cone Penetrometer Test), highly correlated with various testing methods, simple, and economic is being applied. However, it、s hard to utilize DCPT results due to the few numerical analyses for DCPT have been performed and the lack of data accumulation. Therefore, this study tried to verify the validation of numerical modeling for DCPT by comparing and analyzing the results of numerical analyses with field tests. METHODS: The ground elastic modulus and PR(Penetration Rate) value were estimated by using PFC(Particle Flow Code) 3D program based on the discrete element method. Those values were compared and analyzed with the result of field tests. Also, back analysis was conducted to describe ground elastic modulus of field tests. RESULTS : Relative errors of PR value between the numerical analyses and field tests were calculated to be comparatively low. Also, the relationship between elastic modulus and PR value turned out to be similar. CONCLUSIONS : Numerical modeling of DCPT is considered to be suitable for describing field tests by carrying out numerical analysis using PFC 3D program.